Most mahjong rules questions are really one question: something went wrong, now what. A hand got exposed incorrectly, somebody called mahjong and was mistaken, the wall ran out. Here is what the rules say, and what most groups actually do.
What makes a hand dead
A hand is dead when it can no longer legally win. The usual cause is an incorrect exposure: a player calls a tile and lays down a set that does not match any hand on the card, or that cannot combine with what they have already exposed.
Other common causes: holding the wrong number of tiles after a call, exposing a set when the card requires that hand to be concealed, or exposing sets that together are impossible in any single card line.
What a dead hand can still do
A dead hand stays in the game. The player keeps drawing and discarding normally, which matters: they still supply tiles to everyone else and can still throw the tile that wins somebody's hand.
What they cannot do is declare mahjong. In most groups a dead hand still pays the winner at the end, and some groups have the dead player pay a penalty to each opponent instead. Settle which convention your table uses before it comes up.
Calling mahjong when you have not got it
If a player declares mahjong and lays down a hand that turns out not to match a card line, their hand is dead. If they exposed their tiles in the process, the information is now public, which is its own punishment.
The severity varies by group. Casual tables usually just declare the hand dead and play on. Stricter groups require the mistaken caller to pay each opponent the value of the hand they falsely claimed. If tiles from the wall were already disturbed and play cannot resume cleanly, some groups end the hand entirely as a wall game.
The wall game
When the wall runs out and nobody has declared mahjong, the hand is a wall game. No money changes hands. Most groups keep the same dealer and redeal.
Wall games are more common than beginners expect, especially at tables where several players are chasing difficult concealed hands. A hand that ends with nobody paying is a perfectly normal outcome, not a failure of the table.
How to avoid the whole category
Nearly every dead hand traces back to exposing before being certain. Before you call a tile, name the exact card line you are building toward. If you cannot name it, the call is a guess, and guesses are what produce impossible exposures.
The second cause is losing count. After any call, count your tiles before you discard. Thirteen in the rack plus what is exposed, every time.
Put it into practice
Nearly every dead hand starts with exposing a set before you were sure which hand you were building. If you are not certain what your tiles are pointing at, our AI coach reads them and names the direction, with the reasoning, free and with no account.